1. Field of the Invention
The present invention relates to a substrate material for a magnetic head such as a thin film-type magnetic head slider for a hard disk driving device or a thin film-type head for a tape recording device.
2. Description of the Related Art
As a substrate material for a thin film magnetic head, Al.sub.2 O.sub.3 --TiC series substrates have generally been used. In particular, along with recent technical innovations in magnetic heads to attain high recording density (such as reduced size, lowered flying height, and mounted MR elements), various demands have been made also for substrates. In order to cope with such technical changes in magnetic heads, the present applicant has developed an Al.sub.2 O.sub.3 --TiC series substrate material including the advantages of (1) excellent workability for fine fabrication such as ion beam etching (IBE) or reactive ion etching (RIE), with less surface roughness after fabrication and a voidless and fine structure, and (2) reduced dropping of particles and deformation after magnetic annealing (refer to Unexamined Japanese Patent Publication Hei 8-34662).
Further, technical developments has been advanced in order to attain a recording density of 10 Gb/in.sup.2 or higher, and studies have been now been conducted on magnetic heads regarding magnetic elements (MR and GMR elements), thermal stability of micro-recording bits and head-disk interface (HDI).
To satisfy these demands on the magnetic head, the substrate material needs to have the following characteristics in addition to the existent features described above.
(1) Static-free conductivity, since the MR and GMR elements have less durability against discharge destruction at a low voltages. PA1 (2) High rigidity and easy fabrication for controlling the height of magnetic poles, particularly needed because of size reductions and the introduction of GMR in the magnetic head. PA1 (3) Reduced chipping damage, which may lead to the occurrence of matter separating from the head to possibly cause abnormalities in the magnetic resistance change of the MR element (thermal asperity), and high heat conductivity. PA1 (4) Less reactivity, with a lubricant used at the boundary between the disk and the head.
Existing substrate materials cannot satisfy these requirements.